I have a 70's-era Dodge small block I've been trying to sell, trying to determine if it's a 340 or 360, and have been getting conflicting info. Someone led me in the direction of a chart-site I've lost, explaining how "360" could still be stamped on the motor, yet have been made out of a 340 block. I don't mean to 'make waves', just trying to determine if it's a 340, which would really help the much-needed sale. I don't have a chance, lately, to check the crank cap stamping, which has been suggested. # stamped on the lower driver's side: 417-8930-360-1.
Drivers side of the block will be stamped behind the starter and above the soft-plugs. It will say 340 or 360. Passenger side behind the motor mount will tell you the month and the year.
Look on the front of the block below the drivers side head gasket area. There will be a number stamped there. It wil say 340,318 or 360. The area is machined & usually painted eng color. If its a block out of a car ,they were last installed in 73 cars & then went all 360. If the casting date is after 74 ,most likely its a 360 as well. Hope that helps. You can also check out moparts.com . There is a Q&A forum & im sure its been a topic,just search it out.
alot of mopar guys dont seam to know this but the Easiest way is to look at the harmonic balancer, the 360's is huge over a 1 inch 1/8t almost twice as big as a 273,318,340 because it is externally balanced and uses a different crank. Easy quick way to tell, alot of people Tell me I have a 318 in mine and I have to educate them almost no one seams to know this... exception 1972-73 340s were externally balanced so there is a loop hole but very rare so...
Lookin at some of my notes, on the pass. side near the motor mount is that date stamp, " 12 75" followed by "7B". So Dec. '75. Wonder what the 7B means. I don't why, but this stuff always interests me.
I have a 727 I was gonna use with it, on top it's stamped "9 181 C", I was told it came out of an early 70's Cuda. What do the numbers mean?
The real number that you seek for the transmission is located just above the oil pan, drivers side, below the shift lever. Remember that these trannys were often discombobulated internally. I've done a bunch of em.
Very true, the thick balancer means its got a cast crank & after Jan 1 1972 & up 340`s had them & all 360`s in that era as well. I thought he was just asking about the block. Like anything else ,theres always more to it!
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